drivers/nfc/pn533.c

/*
 * Copyright (C) 2011 Instituto Nokia de Tecnologia
 *
 * Authors:
 *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
 *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/nfc.h>
#include <linux/netdevice.h>
#include <net/nfc/nfc.h>

#define VERSION "0.1"

#define PN533_VENDOR_ID 0x4CC
#define PN533_PRODUCT_ID 0x2533

#define SCM_VENDOR_ID 0x4E6
#define SCL3711_PRODUCT_ID 0x5591

static const struct usb_device_id pn533_table[] = {
	{ USB_DEVICE(PN533_VENDOR_ID, PN533_PRODUCT_ID) },
	{ USB_DEVICE(SCM_VENDOR_ID, SCL3711_PRODUCT_ID) },
	{ }
};
MODULE_DEVICE_TABLE(usb, pn533_table);

/* frame definitions */
#define PN533_FRAME_TAIL_SIZE 2
#define PN533_FRAME_SIZE(f) (sizeof(struct pn533_frame) + f->datalen + \
				PN533_FRAME_TAIL_SIZE)
#define PN533_FRAME_ACK_SIZE (sizeof(struct pn533_frame) + 1)
#define PN533_FRAME_CHECKSUM(f) (f->data[f->datalen])
#define PN533_FRAME_POSTAMBLE(f) (f->data[f->datalen + 1])

/* start of frame */
#define PN533_SOF 0x00FF

/* frame identifier: in/out/error */
#define PN533_FRAME_IDENTIFIER(f) (f->data[0])
#define PN533_DIR_OUT 0xD4
#define PN533_DIR_IN 0xD5

/* PN533 Commands */
#define PN533_FRAME_CMD(f) (f->data[1])
#define PN533_FRAME_CMD_PARAMS_PTR(f) (&f->data[2])
#define PN533_FRAME_CMD_PARAMS_LEN(f) (f->datalen - 2)

#define PN533_CMD_GET_FIRMWARE_VERSION 0x02
#define PN533_CMD_RF_CONFIGURATION 0x32
#define PN533_CMD_IN_DATA_EXCHANGE 0x40
#define PN533_CMD_IN_LIST_PASSIVE_TARGET 0x4A
#define PN533_CMD_IN_ATR 0x50
#define PN533_CMD_IN_RELEASE 0x52
#define PN533_CMD_IN_JUMP_FOR_DEP 0x56

#define PN533_CMD_RESPONSE(cmd) (cmd + 1)

/* PN533 Return codes */
#define PN533_CMD_RET_MASK 0x3F
#define PN533_CMD_MI_MASK 0x40
#define PN533_CMD_RET_SUCCESS 0x00

struct pn533;

typedef int (*pn533_cmd_complete_t) (struct pn533 *dev, void *arg,
					u8 *params, int params_len);

/* structs for pn533 commands */

/* PN533_CMD_GET_FIRMWARE_VERSION */
struct pn533_fw_version {
	u8 ic;
	u8 ver;
	u8 rev;
	u8 support;
};

/* PN533_CMD_RF_CONFIGURATION */
#define PN533_CFGITEM_MAX_RETRIES 0x05

#define PN533_CONFIG_MAX_RETRIES_NO_RETRY 0x00
#define PN533_CONFIG_MAX_RETRIES_ENDLESS 0xFF

struct pn533_config_max_retries {
	u8 mx_rty_atr;
	u8 mx_rty_psl;
	u8 mx_rty_passive_act;
} __packed;

/* PN533_CMD_IN_LIST_PASSIVE_TARGET */

/* felica commands opcode */
#define PN533_FELICA_OPC_SENSF_REQ 0
#define PN533_FELICA_OPC_SENSF_RES 1
/* felica SENSF_REQ parameters */
#define PN533_FELICA_SENSF_SC_ALL 0xFFFF
#define PN533_FELICA_SENSF_RC_NO_SYSTEM_CODE 0
#define PN533_FELICA_SENSF_RC_SYSTEM_CODE 1
#define PN533_FELICA_SENSF_RC_ADVANCED_PROTOCOL 2

/* type B initiator_data values */
#define PN533_TYPE_B_AFI_ALL_FAMILIES 0
#define PN533_TYPE_B_POLL_METHOD_TIMESLOT 0
#define PN533_TYPE_B_POLL_METHOD_PROBABILISTIC 1

union pn533_cmd_poll_initdata {
	struct {
		u8 afi;
		u8 polling_method;
	} __packed type_b;
	struct {
		u8 opcode;
		__be16 sc;
		u8 rc;
		u8 tsn;
	} __packed felica;
};

/* Poll modulations */
enum {
	PN533_POLL_MOD_106KBPS_A,
	PN533_POLL_MOD_212KBPS_FELICA,
	PN533_POLL_MOD_424KBPS_FELICA,
	PN533_POLL_MOD_106KBPS_JEWEL,
	PN533_POLL_MOD_847KBPS_B,

	__PN533_POLL_MOD_AFTER_LAST,
};
#define PN533_POLL_MOD_MAX (__PN533_POLL_MOD_AFTER_LAST - 1)

struct pn533_poll_modulations {
	struct {
		u8 maxtg;
		u8 brty;
		union pn533_cmd_poll_initdata initiator_data;
	} __packed data;
	u8 len;
};

const struct pn533_poll_modulations poll_mod[] = {
	[PN533_POLL_MOD_106KBPS_A] = {
		.data = {
			.maxtg = 1,
			.brty = 0,
		},
		.len = 2,
	},
	[PN533_POLL_MOD_212KBPS_FELICA] = {
		.data = {
			.maxtg = 1,
			.brty = 1,
			.initiator_data.felica = {
				.opcode = PN533_FELICA_OPC_SENSF_REQ,
				.sc = PN533_FELICA_SENSF_SC_ALL,
				.rc = PN533_FELICA_SENSF_RC_NO_SYSTEM_CODE,
				.tsn = 0,
			},
		},
		.len = 7,
	},
	[PN533_POLL_MOD_424KBPS_FELICA] = {
		.data = {
			.maxtg = 1,
			.brty = 2,
			.initiator_data.felica = {
				.opcode = PN533_FELICA_OPC_SENSF_REQ,
				.sc = PN533_FELICA_SENSF_SC_ALL,
				.rc = PN533_FELICA_SENSF_RC_NO_SYSTEM_CODE,
				.tsn = 0,
			},
		 },
		.len = 7,
	},
	[PN533_POLL_MOD_106KBPS_JEWEL] = {
		.data = {
			.maxtg = 1,
			.brty = 4,
		},
		.len = 2,
	},
	[PN533_POLL_MOD_847KBPS_B] = {
		.data = {
			.maxtg = 1,
			.brty = 8,
			.initiator_data.type_b = {
				.afi = PN533_TYPE_B_AFI_ALL_FAMILIES,
				.polling_method =
					PN533_TYPE_B_POLL_METHOD_TIMESLOT,
			},
		},
		.len = 3,
	},
};

/* PN533_CMD_IN_ATR */

struct pn533_cmd_activate_param {
	u8 tg;
	u8 next;
} __packed;

struct pn533_cmd_activate_response {
	u8 status;
	u8 nfcid3t[10];
	u8 didt;
	u8 bst;
	u8 brt;
	u8 to;
	u8 ppt;
	/* optional */
	u8 gt[];
} __packed;

/* PN533_CMD_IN_JUMP_FOR_DEP */
struct pn533_cmd_jump_dep {
	u8 active;
	u8 baud;
	u8 next;
	u8 gt[];
} __packed;

struct pn533_cmd_jump_dep_response {
	u8 status;
	u8 tg;
	u8 nfcid3t[10];
	u8 didt;
	u8 bst;
	u8 brt;
	u8 to;
	u8 ppt;
	/* optional */
	u8 gt[];
} __packed;

struct pn533 {
	struct usb_device *udev;
	struct usb_interface *interface;
	struct nfc_dev *nfc_dev;

	struct urb *out_urb;
	int out_maxlen;
	struct pn533_frame *out_frame;

	struct urb *in_urb;
	int in_maxlen;
	struct pn533_frame *in_frame;

	struct tasklet_struct tasklet;
	struct pn533_frame *tklt_in_frame;
	int tklt_in_error;

	pn533_cmd_complete_t cmd_complete;
	void *cmd_complete_arg;
	struct semaphore cmd_lock;
	u8 cmd;

	struct pn533_poll_modulations *poll_mod_active[PN533_POLL_MOD_MAX + 1];
	u8 poll_mod_count;
	u8 poll_mod_curr;
	u32 poll_protocols;

	u8 tgt_available_prots;
	u8 tgt_active_prot;
};

struct pn533_frame {
	u8 preamble;
	__be16 start_frame;
	u8 datalen;
	u8 datalen_checksum;
	u8 data[];
} __packed;

/* The rule: value + checksum = 0 */
static inline u8 pn533_checksum(u8 value)
{
	return ~value + 1;
}

/* The rule: sum(data elements) + checksum = 0 */
static u8 pn533_data_checksum(u8 *data, int datalen)
{
	u8 sum = 0;
	int i;

	for (i = 0; i < datalen; i++)
		sum += data[i];

	return pn533_checksum(sum);
}

/**
 * pn533_tx_frame_ack - create a ack frame
 * @frame:	The frame to be set as ack
 *
 * Ack is different type of standard frame. As a standard frame, it has
 * preamble and start_frame. However the checksum of this frame must fail,
 * i.e. datalen + datalen_checksum must NOT be zero. When the checksum test
 * fails and datalen = 0 and datalen_checksum = 0xFF, the frame is a ack.
 * After datalen_checksum field, the postamble is placed.
 */
static void pn533_tx_frame_ack(struct pn533_frame *frame)
{
	frame->preamble = 0;
	frame->start_frame = cpu_to_be16(PN533_SOF);
	frame->datalen = 0;
	frame->datalen_checksum = 0xFF;
	/* data[0] is used as postamble */
	frame->data[0] = 0;
}

static void pn533_tx_frame_init(struct pn533_frame *frame, u8 cmd)
{
	frame->preamble = 0;
	frame->start_frame = cpu_to_be16(PN533_SOF);
	PN533_FRAME_IDENTIFIER(frame) = PN533_DIR_OUT;
	PN533_FRAME_CMD(frame) = cmd;
	frame->datalen = 2;
}

static void pn533_tx_frame_finish(struct pn533_frame *frame)
{
	frame->datalen_checksum = pn533_checksum(frame->datalen);

	PN533_FRAME_CHECKSUM(frame) =
		pn533_data_checksum(frame->data, frame->datalen);

	PN533_FRAME_POSTAMBLE(frame) = 0;
}

static bool pn533_rx_frame_is_valid(struct pn533_frame *frame)
{
	u8 checksum;

	if (frame->start_frame != cpu_to_be16(PN533_SOF))
		return false;

	checksum = pn533_checksum(frame->datalen);
	if (checksum != frame->datalen_checksum)
		return false;

	checksum = pn533_data_checksum(frame->data, frame->datalen);
	if (checksum != PN533_FRAME_CHECKSUM(frame))
		return false;

	return true;
}

static bool pn533_rx_frame_is_ack(struct pn533_frame *frame)
{
	if (frame->start_frame != cpu_to_be16(PN533_SOF))
		return false;

	if (frame->datalen != 0 || frame->datalen_checksum != 0xFF)
		return false;

	return true;
}

static bool pn533_rx_frame_is_cmd_response(struct pn533_frame *frame, u8 cmd)
{
	return (PN533_FRAME_CMD(frame) == PN533_CMD_RESPONSE(cmd));
}

static void pn533_tasklet_cmd_complete(unsigned long arg)
{
	struct pn533 *dev = (struct pn533 *) arg;
	struct pn533_frame *in_frame = dev->tklt_in_frame;
	int rc;

	if (dev->tklt_in_error)
		rc = dev->cmd_complete(dev, dev->cmd_complete_arg, NULL,
							dev->tklt_in_error);
	else
		rc = dev->cmd_complete(dev, dev->cmd_complete_arg,
					PN533_FRAME_CMD_PARAMS_PTR(in_frame),
					PN533_FRAME_CMD_PARAMS_LEN(in_frame));

	if (rc != -EINPROGRESS)
		up(&dev->cmd_lock);
}

static void pn533_recv_response(struct urb *urb)
{
	struct pn533 *dev = urb->context;
	struct pn533_frame *in_frame;

	dev->tklt_in_frame = NULL;

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		nfc_dev_dbg(&dev->interface->dev, "Urb shutting down with"
						" status: %d", urb->status);
		dev->tklt_in_error = urb->status;
		goto sched_tasklet;
	default:
		nfc_dev_err(&dev->interface->dev, "Nonzero urb status received:"
							" %d", urb->status);
		dev->tklt_in_error = urb->status;
		goto sched_tasklet;
	}

	in_frame = dev->in_urb->transfer_buffer;

	if (!pn533_rx_frame_is_valid(in_frame)) {
		nfc_dev_err(&dev->interface->dev, "Received an invalid frame");
		dev->tklt_in_error = -EIO;
		goto sched_tasklet;
	}

	if (!pn533_rx_frame_is_cmd_response(in_frame, dev->cmd)) {
		nfc_dev_err(&dev->interface->dev, "The received frame is not "
						"response to the last command");
		dev->tklt_in_error = -EIO;
		goto sched_tasklet;
	}

	nfc_dev_dbg(&dev->interface->dev, "Received a valid frame");
	dev->tklt_in_error = 0;
	dev->tklt_in_frame = in_frame;

sched_tasklet:
	tasklet_schedule(&dev->tasklet);
}

static int pn533_submit_urb_for_response(struct pn533 *dev, gfp_t flags)
{
	dev->in_urb->complete = pn533_recv_response;

	return usb_submit_urb(dev->in_urb, flags);
}

static void pn533_recv_ack(struct urb *urb)
{
	struct pn533 *dev = urb->context;
	struct pn533_frame *in_frame;
	int rc;

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		nfc_dev_dbg(&dev->interface->dev, "Urb shutting down with"
						" status: %d", urb->status);
		dev->tklt_in_error = urb->status;
		goto sched_tasklet;
	default:
		nfc_dev_err(&dev->interface->dev, "Nonzero urb status received:"
							" %d", urb->status);
		dev->tklt_in_error = urb->status;
		goto sched_tasklet;
	}

	in_frame = dev->in_urb->transfer_buffer;

	if (!pn533_rx_frame_is_ack(in_frame)) {
		nfc_dev_err(&dev->interface->dev, "Received an invalid ack");
		dev->tklt_in_error = -EIO;
		goto sched_tasklet;
	}

	nfc_dev_dbg(&dev->interface->dev, "Received a valid ack");

	rc = pn533_submit_urb_for_response(dev, GFP_ATOMIC);
	if (rc) {
		nfc_dev_err(&dev->interface->dev, "usb_submit_urb failed with"
							" result %d", rc);
		dev->tklt_in_error = rc;
		goto sched_tasklet;
	}

	return;

sched_tasklet:
	dev->tklt_in_frame = NULL;
	tasklet_schedule(&dev->tasklet);
}

static int pn533_submit_urb_for_ack(struct pn533 *dev, gfp_t flags)
{
	dev->in_urb->complete = pn533_recv_ack;

	return usb_submit_urb(dev->in_urb, flags);
}

static int pn533_send_ack(struct pn533 *dev, gfp_t flags)
{
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	pn533_tx_frame_ack(dev->out_frame);

	dev->out_urb->transfer_buffer = dev->out_frame;
	dev->out_urb->transfer_buffer_length = PN533_FRAME_ACK_SIZE;
	rc = usb_submit_urb(dev->out_urb, flags);

	return rc;
}

static int __pn533_send_cmd_frame_async(struct pn533 *dev,
					struct pn533_frame *out_frame,
					struct pn533_frame *in_frame,
					int in_frame_len,
					pn533_cmd_complete_t cmd_complete,
					void *arg, gfp_t flags)
{
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "Sending command 0x%x",
						PN533_FRAME_CMD(out_frame));

	dev->cmd = PN533_FRAME_CMD(out_frame);
	dev->cmd_complete = cmd_complete;
	dev->cmd_complete_arg = arg;

	dev->out_urb->transfer_buffer = out_frame;
	dev->out_urb->transfer_buffer_length =
				PN533_FRAME_SIZE(out_frame);

	dev->in_urb->transfer_buffer = in_frame;
	dev->in_urb->transfer_buffer_length = in_frame_len;

	rc = usb_submit_urb(dev->out_urb, flags);
	if (rc)
		return rc;

	rc = pn533_submit_urb_for_ack(dev, flags);
	if (rc)
		goto error;

	return 0;

error:
	usb_unlink_urb(dev->out_urb);
	return rc;
}

static int pn533_send_cmd_frame_async(struct pn533 *dev,
					struct pn533_frame *out_frame,
					struct pn533_frame *in_frame,
					int in_frame_len,
					pn533_cmd_complete_t cmd_complete,
					void *arg, gfp_t flags)
{
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	if (down_trylock(&dev->cmd_lock))
		return -EBUSY;

	rc = __pn533_send_cmd_frame_async(dev, out_frame, in_frame,
					in_frame_len, cmd_complete, arg, flags);
	if (rc)
		goto error;

	return 0;
error:
	up(&dev->cmd_lock);
	return rc;
}

struct pn533_sync_cmd_response {
	int rc;
	struct completion done;
};

static int pn533_sync_cmd_complete(struct pn533 *dev, void *_arg,
					u8 *params, int params_len)
{
	struct pn533_sync_cmd_response *arg = _arg;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	arg->rc = 0;

	if (params_len < 0) /* error */
		arg->rc = params_len;

	complete(&arg->done);

	return 0;
}

static int pn533_send_cmd_frame_sync(struct pn533 *dev,
						struct pn533_frame *out_frame,
						struct pn533_frame *in_frame,
						int in_frame_len)
{
	int rc;
	struct pn533_sync_cmd_response arg;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	init_completion(&arg.done);

	rc = pn533_send_cmd_frame_async(dev, out_frame, in_frame, in_frame_len,
				pn533_sync_cmd_complete, &arg, GFP_KERNEL);
	if (rc)
		return rc;

	wait_for_completion(&arg.done);

	return arg.rc;
}

static void pn533_send_complete(struct urb *urb)
{
	struct pn533 *dev = urb->context;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		nfc_dev_dbg(&dev->interface->dev, "Urb shutting down with"
						" status: %d", urb->status);
		break;
	default:
		nfc_dev_dbg(&dev->interface->dev, "Nonzero urb status received:"
							" %d", urb->status);
	}
}

struct pn533_target_type_a {
	__be16 sens_res;
	u8 sel_res;
	u8 nfcid_len;
	u8 nfcid_data[];
} __packed;


#define PN533_TYPE_A_SENS_RES_NFCID1(x) ((u8)((be16_to_cpu(x) & 0x00C0) >> 6))
#define PN533_TYPE_A_SENS_RES_SSD(x) ((u8)((be16_to_cpu(x) & 0x001F) >> 0))
#define PN533_TYPE_A_SENS_RES_PLATCONF(x) ((u8)((be16_to_cpu(x) & 0x0F00) >> 8))

#define PN533_TYPE_A_SENS_RES_SSD_JEWEL 0x00
#define PN533_TYPE_A_SENS_RES_PLATCONF_JEWEL 0x0C

#define PN533_TYPE_A_SEL_PROT(x) (((x) & 0x60) >> 5)
#define PN533_TYPE_A_SEL_CASCADE(x) (((x) & 0x04) >> 2)

#define PN533_TYPE_A_SEL_PROT_MIFARE 0
#define PN533_TYPE_A_SEL_PROT_ISO14443 1
#define PN533_TYPE_A_SEL_PROT_DEP 2
#define PN533_TYPE_A_SEL_PROT_ISO14443_DEP 3

static bool pn533_target_type_a_is_valid(struct pn533_target_type_a *type_a,
							int target_data_len)
{
	u8 ssd;
	u8 platconf;

	if (target_data_len < sizeof(struct pn533_target_type_a))
		return false;

	/* The lenght check of nfcid[] and ats[] are not being performed because
	   the values are not being used */

	/* Requirement 4.6.3.3 from NFC Forum Digital Spec */
	ssd = PN533_TYPE_A_SENS_RES_SSD(type_a->sens_res);
	platconf = PN533_TYPE_A_SENS_RES_PLATCONF(type_a->sens_res);

	if ((ssd == PN533_TYPE_A_SENS_RES_SSD_JEWEL &&
			platconf != PN533_TYPE_A_SENS_RES_PLATCONF_JEWEL) ||
			(ssd != PN533_TYPE_A_SENS_RES_SSD_JEWEL &&
			platconf == PN533_TYPE_A_SENS_RES_PLATCONF_JEWEL))
		return false;

	/* Requirements 4.8.2.1, 4.8.2.3, 4.8.2.5 and 4.8.2.7 from NFC Forum */
	if (PN533_TYPE_A_SEL_CASCADE(type_a->sel_res) != 0)
		return false;

	return true;
}

static int pn533_target_found_type_a(struct nfc_target *nfc_tgt, u8 *tgt_data,
							int tgt_data_len)
{
	struct pn533_target_type_a *tgt_type_a;

	tgt_type_a = (struct pn533_target_type_a *) tgt_data;

	if (!pn533_target_type_a_is_valid(tgt_type_a, tgt_data_len))
		return -EPROTO;

	switch (PN533_TYPE_A_SEL_PROT(tgt_type_a->sel_res)) {
	case PN533_TYPE_A_SEL_PROT_MIFARE:
		nfc_tgt->supported_protocols = NFC_PROTO_MIFARE_MASK;
		break;
	case PN533_TYPE_A_SEL_PROT_ISO14443:
		nfc_tgt->supported_protocols = NFC_PROTO_ISO14443_MASK;
		break;
	case PN533_TYPE_A_SEL_PROT_DEP:
		nfc_tgt->supported_protocols = NFC_PROTO_NFC_DEP_MASK;
		break;
	case PN533_TYPE_A_SEL_PROT_ISO14443_DEP:
		nfc_tgt->supported_protocols = NFC_PROTO_ISO14443_MASK |
							NFC_PROTO_NFC_DEP_MASK;
		break;
	}

	nfc_tgt->sens_res = be16_to_cpu(tgt_type_a->sens_res);
	nfc_tgt->sel_res = tgt_type_a->sel_res;

	return 0;
}

struct pn533_target_felica {
	u8 pol_res;
	u8 opcode;
	u8 nfcid2[8];
	u8 pad[8];
	/* optional */
	u8 syst_code[];
} __packed;

#define PN533_FELICA_SENSF_NFCID2_DEP_B1 0x01
#define PN533_FELICA_SENSF_NFCID2_DEP_B2 0xFE

static bool pn533_target_felica_is_valid(struct pn533_target_felica *felica,
							int target_data_len)
{
	if (target_data_len < sizeof(struct pn533_target_felica))
		return false;

	if (felica->opcode != PN533_FELICA_OPC_SENSF_RES)
		return false;

	return true;
}

static int pn533_target_found_felica(struct nfc_target *nfc_tgt, u8 *tgt_data,
							int tgt_data_len)
{
	struct pn533_target_felica *tgt_felica;

	tgt_felica = (struct pn533_target_felica *) tgt_data;

	if (!pn533_target_felica_is_valid(tgt_felica, tgt_data_len))
		return -EPROTO;

	if (tgt_felica->nfcid2[0] == PN533_FELICA_SENSF_NFCID2_DEP_B1 &&
					tgt_felica->nfcid2[1] ==
					PN533_FELICA_SENSF_NFCID2_DEP_B2)
		nfc_tgt->supported_protocols = NFC_PROTO_NFC_DEP_MASK;
	else
		nfc_tgt->supported_protocols = NFC_PROTO_FELICA_MASK;

	return 0;
}

struct pn533_target_jewel {
	__be16 sens_res;
	u8 jewelid[4];
} __packed;

static bool pn533_target_jewel_is_valid(struct pn533_target_jewel *jewel,
							int target_data_len)
{
	u8 ssd;
	u8 platconf;

	if (target_data_len < sizeof(struct pn533_target_jewel))
		return false;

	/* Requirement 4.6.3.3 from NFC Forum Digital Spec */
	ssd = PN533_TYPE_A_SENS_RES_SSD(jewel->sens_res);
	platconf = PN533_TYPE_A_SENS_RES_PLATCONF(jewel->sens_res);

	if ((ssd == PN533_TYPE_A_SENS_RES_SSD_JEWEL &&
			platconf != PN533_TYPE_A_SENS_RES_PLATCONF_JEWEL) ||
			(ssd != PN533_TYPE_A_SENS_RES_SSD_JEWEL &&
			platconf == PN533_TYPE_A_SENS_RES_PLATCONF_JEWEL))
		return false;

	return true;
}

static int pn533_target_found_jewel(struct nfc_target *nfc_tgt, u8 *tgt_data,
							int tgt_data_len)
{
	struct pn533_target_jewel *tgt_jewel;

	tgt_jewel = (struct pn533_target_jewel *) tgt_data;

	if (!pn533_target_jewel_is_valid(tgt_jewel, tgt_data_len))
		return -EPROTO;

	nfc_tgt->supported_protocols = NFC_PROTO_JEWEL_MASK;
	nfc_tgt->sens_res = be16_to_cpu(tgt_jewel->sens_res);

	return 0;
}

struct pn533_type_b_prot_info {
	u8 bitrate;
	u8 fsci_type;
	u8 fwi_adc_fo;
} __packed;

#define PN533_TYPE_B_PROT_FCSI(x) (((x) & 0xF0) >> 4)
#define PN533_TYPE_B_PROT_TYPE(x) (((x) & 0x0F) >> 0)
#define PN533_TYPE_B_PROT_TYPE_RFU_MASK 0x8

struct pn533_type_b_sens_res {
	u8 opcode;
	u8 nfcid[4];
	u8 appdata[4];
	struct pn533_type_b_prot_info prot_info;
} __packed;

#define PN533_TYPE_B_OPC_SENSB_RES 0x50

struct pn533_target_type_b {
	struct pn533_type_b_sens_res sensb_res;
	u8 attrib_res_len;
	u8 attrib_res[];
} __packed;

static bool pn533_target_type_b_is_valid(struct pn533_target_type_b *type_b,
							int target_data_len)
{
	if (target_data_len < sizeof(struct pn533_target_type_b))
		return false;

	if (type_b->sensb_res.opcode != PN533_TYPE_B_OPC_SENSB_RES)
		return false;

	if (PN533_TYPE_B_PROT_TYPE(type_b->sensb_res.prot_info.fsci_type) &
						PN533_TYPE_B_PROT_TYPE_RFU_MASK)
		return false;

	return true;
}

static int pn533_target_found_type_b(struct nfc_target *nfc_tgt, u8 *tgt_data,
							int tgt_data_len)
{
	struct pn533_target_type_b *tgt_type_b;

	tgt_type_b = (struct pn533_target_type_b *) tgt_data;

	if (!pn533_target_type_b_is_valid(tgt_type_b, tgt_data_len))
		return -EPROTO;

	nfc_tgt->supported_protocols = NFC_PROTO_ISO14443_MASK;

	return 0;
}

struct pn533_poll_response {
	u8 nbtg;
	u8 tg;
	u8 target_data[];
} __packed;

static int pn533_target_found(struct pn533 *dev,
			struct pn533_poll_response *resp, int resp_len)
{
	int target_data_len;
	struct nfc_target nfc_tgt;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s - modulation=%d", __func__,
							dev->poll_mod_curr);

	if (resp->tg != 1)
		return -EPROTO;

	target_data_len = resp_len - sizeof(struct pn533_poll_response);

	switch (dev->poll_mod_curr) {
	case PN533_POLL_MOD_106KBPS_A:
		rc = pn533_target_found_type_a(&nfc_tgt, resp->target_data,
							target_data_len);
		break;
	case PN533_POLL_MOD_212KBPS_FELICA:
	case PN533_POLL_MOD_424KBPS_FELICA:
		rc = pn533_target_found_felica(&nfc_tgt, resp->target_data,
							target_data_len);
		break;
	case PN533_POLL_MOD_106KBPS_JEWEL:
		rc = pn533_target_found_jewel(&nfc_tgt, resp->target_data,
							target_data_len);
		break;
	case PN533_POLL_MOD_847KBPS_B:
		rc = pn533_target_found_type_b(&nfc_tgt, resp->target_data,
							target_data_len);
		break;
	default:
		nfc_dev_err(&dev->interface->dev, "Unknown current poll"
								" modulation");
		return -EPROTO;
	}

	if (rc)
		return rc;

	if (!(nfc_tgt.supported_protocols & dev->poll_protocols)) {
		nfc_dev_dbg(&dev->interface->dev, "The target found does not"
						" have the desired protocol");
		return -EAGAIN;
	}

	nfc_dev_dbg(&dev->interface->dev, "Target found - supported protocols: "
					"0x%x", nfc_tgt.supported_protocols);

	dev->tgt_available_prots = nfc_tgt.supported_protocols;

	nfc_targets_found(dev->nfc_dev, &nfc_tgt, 1);

	return 0;
}

static void pn533_poll_reset_mod_list(struct pn533 *dev)
{
	dev->poll_mod_count = 0;
}

static void pn533_poll_add_mod(struct pn533 *dev, u8 mod_index)
{
	dev->poll_mod_active[dev->poll_mod_count] =
		(struct pn533_poll_modulations *) &poll_mod[mod_index];
	dev->poll_mod_count++;
}

static void pn533_poll_create_mod_list(struct pn533 *dev, u32 protocols)
{
	pn533_poll_reset_mod_list(dev);

	if (protocols & NFC_PROTO_MIFARE_MASK
					|| protocols & NFC_PROTO_ISO14443_MASK
					|| protocols & NFC_PROTO_NFC_DEP_MASK)
		pn533_poll_add_mod(dev, PN533_POLL_MOD_106KBPS_A);

	if (protocols & NFC_PROTO_FELICA_MASK
					|| protocols & NFC_PROTO_NFC_DEP_MASK) {
		pn533_poll_add_mod(dev, PN533_POLL_MOD_212KBPS_FELICA);
		pn533_poll_add_mod(dev, PN533_POLL_MOD_424KBPS_FELICA);
	}

	if (protocols & NFC_PROTO_JEWEL_MASK)
		pn533_poll_add_mod(dev, PN533_POLL_MOD_106KBPS_JEWEL);

	if (protocols & NFC_PROTO_ISO14443_MASK)
		pn533_poll_add_mod(dev, PN533_POLL_MOD_847KBPS_B);
}

static void pn533_start_poll_frame(struct pn533_frame *frame,
					struct pn533_poll_modulations *mod)
{

	pn533_tx_frame_init(frame, PN533_CMD_IN_LIST_PASSIVE_TARGET);

	memcpy(PN533_FRAME_CMD_PARAMS_PTR(frame), &mod->data, mod->len);
	frame->datalen += mod->len;

	pn533_tx_frame_finish(frame);
}

static int pn533_start_poll_complete(struct pn533 *dev, void *arg,
						u8 *params, int params_len)
{
	struct pn533_poll_response *resp;
	struct pn533_poll_modulations *next_mod;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	if (params_len == -ENOENT) {
		nfc_dev_dbg(&dev->interface->dev, "Polling operation has been"
								" stopped");
		goto stop_poll;
	}

	if (params_len < 0) {
		nfc_dev_err(&dev->interface->dev, "Error %d when running poll",
								params_len);
		goto stop_poll;
	}

	resp = (struct pn533_poll_response *) params;
	if (resp->nbtg) {
		rc = pn533_target_found(dev, resp, params_len);

		/* We must stop the poll after a valid target found */
		if (rc == 0)
			goto stop_poll;

		if (rc != -EAGAIN)
			nfc_dev_err(&dev->interface->dev, "The target found is"
					" not valid - continuing to poll");
	}

	dev->poll_mod_curr = (dev->poll_mod_curr + 1) % dev->poll_mod_count;

	next_mod = dev->poll_mod_active[dev->poll_mod_curr];

	nfc_dev_dbg(&dev->interface->dev, "Polling next modulation (0x%x)",
							dev->poll_mod_curr);

	pn533_start_poll_frame(dev->out_frame, next_mod);

	/* Don't need to down the semaphore again */
	rc = __pn533_send_cmd_frame_async(dev, dev->out_frame, dev->in_frame,
				dev->in_maxlen, pn533_start_poll_complete,
				NULL, GFP_ATOMIC);

	if (rc == -EPERM) {
		nfc_dev_dbg(&dev->interface->dev, "Cannot poll next modulation"
					" because poll has been stopped");
		goto stop_poll;
	}

	if (rc) {
		nfc_dev_err(&dev->interface->dev, "Error %d when trying to poll"
							" next modulation", rc);
		goto stop_poll;
	}

	/* Inform caller function to do not up the semaphore */
	return -EINPROGRESS;

stop_poll:
	pn533_poll_reset_mod_list(dev);
	dev->poll_protocols = 0;
	return 0;
}

static int pn533_start_poll(struct nfc_dev *nfc_dev, u32 protocols)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	struct pn533_poll_modulations *start_mod;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s - protocols=0x%x", __func__,
								protocols);

	if (dev->poll_mod_count) {
		nfc_dev_err(&dev->interface->dev, "Polling operation already"
								" active");
		return -EBUSY;
	}

	if (dev->tgt_active_prot) {
		nfc_dev_err(&dev->interface->dev, "Cannot poll with a target"
							" already activated");
		return -EBUSY;
	}

	pn533_poll_create_mod_list(dev, protocols);

	if (!dev->poll_mod_count) {
		nfc_dev_err(&dev->interface->dev, "No valid protocols"
								" specified");
		rc = -EINVAL;
		goto error;
	}

	nfc_dev_dbg(&dev->interface->dev, "It will poll %d modulations types",
							dev->poll_mod_count);

	dev->poll_mod_curr = 0;
	start_mod = dev->poll_mod_active[dev->poll_mod_curr];

	pn533_start_poll_frame(dev->out_frame, start_mod);

	rc = pn533_send_cmd_frame_async(dev, dev->out_frame, dev->in_frame,
				dev->in_maxlen,	pn533_start_poll_complete,
				NULL, GFP_KERNEL);

	if (rc) {
		nfc_dev_err(&dev->interface->dev, "Error %d when trying to"
							" start poll", rc);
		goto error;
	}

	dev->poll_protocols = protocols;

	return 0;

error:
	pn533_poll_reset_mod_list(dev);
	return rc;
}

static void pn533_stop_poll(struct nfc_dev *nfc_dev)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	if (!dev->poll_mod_count) {
		nfc_dev_dbg(&dev->interface->dev, "Polling operation was not"
								" running");
		return;
	}

	/* An ack will cancel the last issued command (poll) */
	pn533_send_ack(dev, GFP_KERNEL);

	/* prevent pn533_start_poll_complete to issue a new poll meanwhile */
	usb_kill_urb(dev->in_urb);
}

static int pn533_activate_target_nfcdep(struct pn533 *dev)
{
	struct pn533_cmd_activate_param param;
	struct pn533_cmd_activate_response *resp;
	u16 gt_len;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	pn533_tx_frame_init(dev->out_frame, PN533_CMD_IN_ATR);

	param.tg = 1;
	param.next = 0;
	memcpy(PN533_FRAME_CMD_PARAMS_PTR(dev->out_frame), &param,
				sizeof(struct pn533_cmd_activate_param));
	dev->out_frame->datalen += sizeof(struct pn533_cmd_activate_param);

	pn533_tx_frame_finish(dev->out_frame);

	rc = pn533_send_cmd_frame_sync(dev, dev->out_frame, dev->in_frame,
								dev->in_maxlen);
	if (rc)
		return rc;

	resp = (struct pn533_cmd_activate_response *)
				PN533_FRAME_CMD_PARAMS_PTR(dev->in_frame);
	rc = resp->status & PN533_CMD_RET_MASK;
	if (rc != PN533_CMD_RET_SUCCESS)
		return -EIO;

	/* ATR_RES general bytes are located at offset 16 */
	gt_len = PN533_FRAME_CMD_PARAMS_LEN(dev->in_frame) - 16;
	rc = nfc_set_remote_general_bytes(dev->nfc_dev, resp->gt, gt_len);

	return rc;
}

static int pn533_activate_target(struct nfc_dev *nfc_dev, u32 target_idx,
								u32 protocol)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s - protocol=%u", __func__,
								protocol);

	if (dev->poll_mod_count) {
		nfc_dev_err(&dev->interface->dev, "Cannot activate while"
								" polling");
		return -EBUSY;
	}

	if (dev->tgt_active_prot) {
		nfc_dev_err(&dev->interface->dev, "There is already an active"
								" target");
		return -EBUSY;
	}

	if (!dev->tgt_available_prots) {
		nfc_dev_err(&dev->interface->dev, "There is no available target"
								" to activate");
		return -EINVAL;
	}

	if (!(dev->tgt_available_prots & (1 << protocol))) {
		nfc_dev_err(&dev->interface->dev, "The target does not support"
					" the requested protocol %u", protocol);
		return -EINVAL;
	}

	if (protocol == NFC_PROTO_NFC_DEP) {
		rc = pn533_activate_target_nfcdep(dev);
		if (rc) {
			nfc_dev_err(&dev->interface->dev, "Error %d when"
						" activating target with"
						" NFC_DEP protocol", rc);
			return rc;
		}
	}

	dev->tgt_active_prot = protocol;
	dev->tgt_available_prots = 0;

	return 0;
}

static void pn533_deactivate_target(struct nfc_dev *nfc_dev, u32 target_idx)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	u8 tg;
	u8 status;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	if (!dev->tgt_active_prot) {
		nfc_dev_err(&dev->interface->dev, "There is no active target");
		return;
	}

	dev->tgt_active_prot = 0;

	pn533_tx_frame_init(dev->out_frame, PN533_CMD_IN_RELEASE);

	tg = 1;
	memcpy(PN533_FRAME_CMD_PARAMS_PTR(dev->out_frame), &tg, sizeof(u8));
	dev->out_frame->datalen += sizeof(u8);

	pn533_tx_frame_finish(dev->out_frame);

	rc = pn533_send_cmd_frame_sync(dev, dev->out_frame, dev->in_frame,
								dev->in_maxlen);
	if (rc) {
		nfc_dev_err(&dev->interface->dev, "Error when sending release"
						" command to the controller");
		return;
	}

	status = PN533_FRAME_CMD_PARAMS_PTR(dev->in_frame)[0];
	rc = status & PN533_CMD_RET_MASK;
	if (rc != PN533_CMD_RET_SUCCESS)
		nfc_dev_err(&dev->interface->dev, "Error 0x%x when releasing"
							" the target", rc);

	return;
}


static int pn533_in_dep_link_up_complete(struct pn533 *dev, void *arg,
						u8 *params, int params_len)
{
	struct pn533_cmd_jump_dep *cmd;
	struct pn533_cmd_jump_dep_response *resp;
	struct nfc_target nfc_target;
	u8 target_gt_len;
	int rc;

	if (params_len == -ENOENT) {
		nfc_dev_dbg(&dev->interface->dev, "");
		return 0;
	}

	if (params_len < 0) {
		nfc_dev_err(&dev->interface->dev,
				"Error %d when bringing DEP link up",
								params_len);
		return 0;
	}

	if (dev->tgt_available_prots &&
	    !(dev->tgt_available_prots & (1 << NFC_PROTO_NFC_DEP))) {
		nfc_dev_err(&dev->interface->dev,
			"The target does not support DEP");
		return -EINVAL;
	}

	resp = (struct pn533_cmd_jump_dep_response *) params;
	cmd = (struct pn533_cmd_jump_dep *) arg;
	rc = resp->status & PN533_CMD_RET_MASK;
	if (rc != PN533_CMD_RET_SUCCESS) {
		nfc_dev_err(&dev->interface->dev,
				"Bringing DEP link up failed %d", rc);
		return 0;
	}

	if (!dev->tgt_available_prots) {
		nfc_dev_dbg(&dev->interface->dev, "Creating new target");

		nfc_target.supported_protocols = NFC_PROTO_NFC_DEP_MASK;
		rc = nfc_targets_found(dev->nfc_dev, &nfc_target, 1);
		if (rc)
			return 0;

		dev->tgt_available_prots = 0;
	}

	dev->tgt_active_prot = NFC_PROTO_NFC_DEP;

	/* ATR_RES general bytes are located at offset 17 */
	target_gt_len = PN533_FRAME_CMD_PARAMS_LEN(dev->in_frame) - 17;
	rc = nfc_set_remote_general_bytes(dev->nfc_dev,
						resp->gt, target_gt_len);
	if (rc == 0)
		rc = nfc_dep_link_is_up(dev->nfc_dev,
						dev->nfc_dev->targets[0].idx,
						!cmd->active, NFC_RF_INITIATOR);

	return 0;
}

static int pn533_dep_link_up(struct nfc_dev *nfc_dev, int target_idx,
						u8 comm_mode, u8 rf_mode)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	struct pn533_cmd_jump_dep *cmd;
	u8 cmd_len, local_gt_len, *local_gt;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	if (rf_mode == NFC_RF_TARGET) {
		nfc_dev_err(&dev->interface->dev, "Target mode not supported");
		return -EOPNOTSUPP;
	}


	if (dev->poll_mod_count) {
		nfc_dev_err(&dev->interface->dev,
				"Cannot bring the DEP link up while polling");
		return -EBUSY;
	}

	if (dev->tgt_active_prot) {
		nfc_dev_err(&dev->interface->dev,
				"There is already an active target");
		return -EBUSY;
	}

	local_gt = nfc_get_local_general_bytes(dev->nfc_dev, &local_gt_len);
	if (local_gt_len > NFC_MAX_GT_LEN)
		return -EINVAL;

	cmd_len = sizeof(struct pn533_cmd_jump_dep) + local_gt_len;
	cmd = kzalloc(cmd_len, GFP_KERNEL);
	if (cmd == NULL)
		return -ENOMEM;

	pn533_tx_frame_init(dev->out_frame, PN533_CMD_IN_JUMP_FOR_DEP);

	cmd->active = !comm_mode;
	cmd->baud = 0;
	if (local_gt != NULL) {
		cmd->next = 4; /* We have some Gi */
		memcpy(cmd->gt, local_gt, local_gt_len);
	} else {
		cmd->next = 0;
	}

	memcpy(PN533_FRAME_CMD_PARAMS_PTR(dev->out_frame), cmd, cmd_len);
	dev->out_frame->datalen += cmd_len;

	pn533_tx_frame_finish(dev->out_frame);

	rc = pn533_send_cmd_frame_async(dev, dev->out_frame, dev->in_frame,
				dev->in_maxlen,	pn533_in_dep_link_up_complete,
				cmd, GFP_KERNEL);
	if (rc)
		goto out;


out:
	kfree(cmd);

	return rc;
}

static int pn533_dep_link_down(struct nfc_dev *nfc_dev)
{
	pn533_deactivate_target(nfc_dev, 0);

	return 0;
}

#define PN533_CMD_DATAEXCH_HEAD_LEN (sizeof(struct pn533_frame) + 3)
#define PN533_CMD_DATAEXCH_DATA_MAXLEN 262

static int pn533_data_exchange_tx_frame(struct pn533 *dev, struct sk_buff *skb)
{
	int payload_len = skb->len;
	struct pn533_frame *out_frame;
	u8 tg;

	nfc_dev_dbg(&dev->interface->dev, "%s - Sending %d bytes", __func__,
								payload_len);

	if (payload_len > PN533_CMD_DATAEXCH_DATA_MAXLEN) {
		/* TODO: Implement support to multi-part data exchange */
		nfc_dev_err(&dev->interface->dev, "Data length greater than the"
						" max allowed: %d",
						PN533_CMD_DATAEXCH_DATA_MAXLEN);
		return -ENOSYS;
	}

	skb_push(skb, PN533_CMD_DATAEXCH_HEAD_LEN);
	out_frame = (struct pn533_frame *) skb->data;

	pn533_tx_frame_init(out_frame, PN533_CMD_IN_DATA_EXCHANGE);

	tg = 1;
	memcpy(PN533_FRAME_CMD_PARAMS_PTR(out_frame), &tg, sizeof(u8));
	out_frame->datalen += sizeof(u8);

	/* The data is already in the out_frame, just update the datalen */
	out_frame->datalen += payload_len;

	pn533_tx_frame_finish(out_frame);
	skb_put(skb, PN533_FRAME_TAIL_SIZE);

	return 0;
}

struct pn533_data_exchange_arg {
	struct sk_buff *skb_resp;
	struct sk_buff *skb_out;
	data_exchange_cb_t cb;
	void *cb_context;
};

static int pn533_data_exchange_complete(struct pn533 *dev, void *_arg,
						u8 *params, int params_len)
{
	struct pn533_data_exchange_arg *arg = _arg;
	struct sk_buff *skb_resp = arg->skb_resp;
	struct pn533_frame *in_frame = (struct pn533_frame *) skb_resp->data;
	int err = 0;
	u8 status;
	u8 cmd_ret;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	dev_kfree_skb_irq(arg->skb_out);

	if (params_len < 0) { /* error */
		err = params_len;
		goto error;
	}

	skb_put(skb_resp, PN533_FRAME_SIZE(in_frame));

	status = params[0];

	cmd_ret = status & PN533_CMD_RET_MASK;
	if (cmd_ret != PN533_CMD_RET_SUCCESS) {
		nfc_dev_err(&dev->interface->dev, "PN533 reported error %d when"
						" exchanging data", cmd_ret);
		err = -EIO;
		goto error;
	}

	if (status & PN533_CMD_MI_MASK) {
		/* TODO: Implement support to multi-part data exchange */
		nfc_dev_err(&dev->interface->dev, "Multi-part message not yet"
								" supported");
		/* Prevent the other messages from controller */
		pn533_send_ack(dev, GFP_ATOMIC);
		err = -ENOSYS;
		goto error;
	}

	skb_pull(skb_resp, PN533_CMD_DATAEXCH_HEAD_LEN);
	skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_SIZE);

	arg->cb(arg->cb_context, skb_resp, 0);
	kfree(arg);
	return 0;

error:
	dev_kfree_skb_irq(skb_resp);
	arg->cb(arg->cb_context, NULL, err);
	kfree(arg);
	return 0;
}

static int pn533_data_exchange(struct nfc_dev *nfc_dev, u32 target_idx,
						struct sk_buff *skb,
						data_exchange_cb_t cb,
						void *cb_context)
{
	struct pn533 *dev = nfc_get_drvdata(nfc_dev);
	struct pn533_frame *out_frame, *in_frame;
	struct pn533_data_exchange_arg *arg;
	struct sk_buff *skb_resp;
	int skb_resp_len;
	int rc;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	if (!dev->tgt_active_prot) {
		nfc_dev_err(&dev->interface->dev, "Cannot exchange data if"
						" there is no active target");
		rc = -EINVAL;
		goto error;
	}

	rc = pn533_data_exchange_tx_frame(dev, skb);
	if (rc)
		goto error;

	skb_resp_len = PN533_CMD_DATAEXCH_HEAD_LEN +
			PN533_CMD_DATAEXCH_DATA_MAXLEN +
			PN533_FRAME_TAIL_SIZE;

	skb_resp = nfc_alloc_recv_skb(skb_resp_len, GFP_KERNEL);
	if (!skb_resp) {
		rc = -ENOMEM;
		goto error;
	}

	in_frame = (struct pn533_frame *) skb_resp->data;
	out_frame = (struct pn533_frame *) skb->data;

	arg = kmalloc(sizeof(struct pn533_data_exchange_arg), GFP_KERNEL);
	if (!arg) {
		rc = -ENOMEM;
		goto free_skb_resp;
	}

	arg->skb_resp = skb_resp;
	arg->skb_out = skb;
	arg->cb = cb;
	arg->cb_context = cb_context;

	rc = pn533_send_cmd_frame_async(dev, out_frame, in_frame, skb_resp_len,
					pn533_data_exchange_complete, arg,
					GFP_KERNEL);
	if (rc) {
		nfc_dev_err(&dev->interface->dev, "Error %d when trying to"
						" perform data_exchange", rc);
		goto free_arg;
	}

	return 0;

free_arg:
	kfree(arg);
free_skb_resp:
	kfree_skb(skb_resp);
error:
	kfree_skb(skb);
	return rc;
}

static int pn533_set_configuration(struct pn533 *dev, u8 cfgitem, u8 *cfgdata,
								u8 cfgdata_len)
{
	int rc;
	u8 *params;

	nfc_dev_dbg(&dev->interface->dev, "%s", __func__);

	pn533_tx_frame_init(dev->out_frame, PN533_CMD_RF_CONFIGURATION);

	params = PN533_FRAME_CMD_PARAMS_PTR(dev->out_frame);
	params[0] = cfgitem;
	memcpy(&params[1], cfgdata, cfgdata_len);
	dev->out_frame->datalen += (1 + cfgdata_len);

	pn533_tx_frame_finish(dev->out_frame);

	rc = pn533_send_cmd_frame_sync(dev, dev->out_frame, dev->in_frame,
								dev->in_maxlen);

	return rc;
}

struct nfc_ops pn533_nfc_ops = {
	.dev_up = NULL,
	.dev_down = NULL,
	.dep_link_up = pn533_dep_link_up,
	.dep_link_down = pn533_dep_link_down,
	.start_poll = pn533_start_poll,
	.stop_poll = pn533_stop_poll,
	.activate_target = pn533_activate_target,
	.deactivate_target = pn533_deactivate_target,
	.data_exchange = pn533_data_exchange,
};

static int pn533_probe(struct usb_interface *interface,
			const struct usb_device_id *id)
{
	struct pn533_fw_version *fw_ver;
	struct pn533 *dev;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	struct pn533_config_max_retries max_retries;
	int in_endpoint = 0;
	int out_endpoint = 0;
	int rc = -ENOMEM;
	int i;
	u32 protocols;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;
	sema_init(&dev->cmd_lock, 1);

	iface_desc = interface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		if (!in_endpoint && usb_endpoint_is_bulk_in(endpoint)) {
			dev->in_maxlen = le16_to_cpu(endpoint->wMaxPacketSize);
			in_endpoint = endpoint->bEndpointAddress;
		}

		if (!out_endpoint && usb_endpoint_is_bulk_out(endpoint)) {
			dev->out_maxlen =
				le16_to_cpu(endpoint->wMaxPacketSize);
			out_endpoint = endpoint->bEndpointAddress;
		}
	}

	if (!in_endpoint || !out_endpoint) {
		nfc_dev_err(&interface->dev, "Could not find bulk-in or"
							" bulk-out endpoint");
		rc = -ENODEV;
		goto error;
	}

	dev->in_frame = kmalloc(dev->in_maxlen, GFP_KERNEL);
	dev->in_urb = usb_alloc_urb(0, GFP_KERNEL);
	dev->out_frame = kmalloc(dev->out_maxlen, GFP_KERNEL);
	dev->out_urb = usb_alloc_urb(0, GFP_KERNEL);

	if (!dev->in_frame || !dev->out_frame ||
		!dev->in_urb || !dev->out_urb)
		goto error;

	usb_fill_bulk_urb(dev->in_urb, dev->udev,
			usb_rcvbulkpipe(dev->udev, in_endpoint),
			NULL, 0, NULL, dev);
	usb_fill_bulk_urb(dev->out_urb, dev->udev,
			usb_sndbulkpipe(dev->udev, out_endpoint),
			NULL, 0,
			pn533_send_complete, dev);

	tasklet_init(&dev->tasklet, pn533_tasklet_cmd_complete, (ulong)dev);

	usb_set_intfdata(interface, dev);

	pn533_tx_frame_init(dev->out_frame, PN533_CMD_GET_FIRMWARE_VERSION);
	pn533_tx_frame_finish(dev->out_frame);

	rc = pn533_send_cmd_frame_sync(dev, dev->out_frame, dev->in_frame,
								dev->in_maxlen);
	if (rc)
		goto kill_tasklet;

	fw_ver = (struct pn533_fw_version *)
				PN533_FRAME_CMD_PARAMS_PTR(dev->in_frame);
	nfc_dev_info(&dev->interface->dev, "NXP PN533 firmware ver %d.%d now"
					" attached", fw_ver->ver, fw_ver->rev);

	protocols = NFC_PROTO_JEWEL_MASK
			| NFC_PROTO_MIFARE_MASK | NFC_PROTO_FELICA_MASK
			| NFC_PROTO_ISO14443_MASK
			| NFC_PROTO_NFC_DEP_MASK;

	dev->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols,
					   PN533_CMD_DATAEXCH_HEAD_LEN,
					   PN533_FRAME_TAIL_SIZE);
	if (!dev->nfc_dev)
		goto kill_tasklet;

	nfc_set_parent_dev(dev->nfc_dev, &interface->dev);
	nfc_set_drvdata(dev->nfc_dev, dev);

	rc = nfc_register_device(dev->nfc_dev);
	if (rc)
		goto free_nfc_dev;

	max_retries.mx_rty_atr = PN533_CONFIG_MAX_RETRIES_ENDLESS;
	max_retries.mx_rty_psl = 2;
	max_retries.mx_rty_passive_act = PN533_CONFIG_MAX_RETRIES_NO_RETRY;

	rc = pn533_set_configuration(dev, PN533_CFGITEM_MAX_RETRIES,
				(u8 *) &max_retries, sizeof(max_retries));

	if (rc) {
		nfc_dev_err(&dev->interface->dev, "Error on setting MAX_RETRIES"
								" config");
		goto free_nfc_dev;
	}

	return 0;

free_nfc_dev:
	nfc_free_device(dev->nfc_dev);
kill_tasklet:
	tasklet_kill(&dev->tasklet);
error:
	kfree(dev->in_frame);
	usb_free_urb(dev->in_urb);
	kfree(dev->out_frame);
	usb_free_urb(dev->out_urb);
	kfree(dev);
	return rc;
}

static void pn533_disconnect(struct usb_interface *interface)
{
	struct pn533 *dev;

	dev = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

	nfc_unregister_device(dev->nfc_dev);
	nfc_free_device(dev->nfc_dev);

	usb_kill_urb(dev->in_urb);
	usb_kill_urb(dev->out_urb);

	tasklet_kill(&dev->tasklet);

	kfree(dev->in_frame);
	usb_free_urb(dev->in_urb);
	kfree(dev->out_frame);
	usb_free_urb(dev->out_urb);
	kfree(dev);

	nfc_dev_info(&interface->dev, "NXP PN533 NFC device disconnected");
}

static struct usb_driver pn533_driver = {
	.name =		"pn533",
	.probe =	pn533_probe,
	.disconnect =	pn533_disconnect,
	.id_table =	pn533_table,
};

static int __init pn533_init(void)
{
	int rc;

	rc = usb_register(&pn533_driver);
	if (rc)
		err("usb_register failed. Error number %d", rc);

	return rc;
}

static void __exit pn533_exit(void)
{
	usb_deregister(&pn533_driver);
}

module_init(pn533_init);
module_exit(pn533_exit);

MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@openbossa.org>,"
			" Aloisio Almeida Jr <aloisio.almeida@openbossa.org>");
MODULE_DESCRIPTION("PN533 usb driver ver " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");